from datetime import datetime

from sqlalchemy import (Boolean, Column, DateTime, Float, ForeignKey, Index,
                        Integer, String, Text, UniqueConstraint)
from sqlalchemy.orm import relationship

# Import Base from the central database module instead of creating a new one
from app.core.database import Base
from models.database.base import TimestampMixin

class Stock(Base, TimestampMixin):
    __tablename__ = "stock"

    id = Column(Integer, primary_key=True, index=True)
    gtin = Column(
        String, index=True, nullable=False
    )  # Foreign key relationship would be ideal
    location = Column(String, nullable=False, index=True)
    quantity = Column(Integer, nullable=False, default=0)
    reserved_quantity = Column(Integer, default=0)  # For orders being processed
    vendor_id = Column(Integer, ForeignKey("vendors.id"))  # Optional: vendor -specific stock

    # Relationships
    vendor = relationship("Shop")

    # Composite unique constraint to prevent duplicate GTIN-location combinations
    __table_args__ = (
        UniqueConstraint("gtin", "location", name="uq_stock_gtin_location"),
        Index(
            "idx_stock_gtin_location", "gtin", "location"
        ),  # Composite index for efficient queries
    )

    def __repr__(self):
        return f"<Stock(gtin='{self.gtin}', location='{self.location}', quantity={self.quantity})>"